A conventional buckle device for skate boots or in-line skate generally includes a securing means on one flap of the boot and a lock member on the other flap of the boot, wherein the lock member is pivotably connected to a frame. A toothed belt has a first end thereof fixedly connected to a head pivotably connected to the lock member and a second end of the toothed belt can be secured in the securing means. The lock member is a U-shaped member and the frame and the head are pivotably connected to the lock member at different points. When fastening the belt, the first end of the belt is firstly secured in the securing means and then the lock member is pushed to pull the belt tightly. However, the lock member tends to be lifted unintentionally because there has no safety means connected to the lock member and once the buckle is opened, the ankle of the wearer could be hurt.
The present invention intends to provide a buckle device that has a tongue retractably received in the lock member so that the lock member cannot be lifted except that the tongue is first pushed.